Locomotive screw-jack.



C. A. HARDY & R. H. BOURNE.

LOCOMOTIVE SCREW JACK. APPLICATION FILED APR. 27. 1914.

Patented Mar. 28, 1916.

2 SHEETS-SHEET I.

C. A. HARDY R. H. BOURNE.

LOCOMOTIVE SCREW JACK. APPLICATION FILED APR. 27. I914.

Patented Mar. 28, 1916.

. 2 SHEETS-SHEET 2.

TED STATES PATENT orFroE.

cnnmnn'r A. HAR Y AND RALPH H. BOURNE, or cnrcneo, rumors, ASSIGNORS TO .wnrrINe FOUNDRY EQUIPMENT COMPANY, or HARVEY, rumors, A. CORPORA- ,TION OF ILLINOIS.

nocoivrorrvn SCREW-JACK.

Application filed April 27, 1914. Serial No. 834,570.

To all whom it may concern Be it known that we, CLEMENT A. HARDY I and RALPH H. BoURNE, residing'at Chicago,

Cook countyfIllinois, both citizens of the United States, have invented a certain new and useful Improvement in Locomotive Screw-Jacks, of which the following is a Specification.

This invention relates to screw jacks for lifting heavy objects, but it is particularly applicable to the general class of devices used for lifting heavy locomotives from a railroad track for repair and other purposes. ()ne form of these devices is illustrated in Patent No. 1,085,734 to C. A. Hardy, February 3rd, 1914, and another is shown in an M application now pending, Serial No. 665,082.

The object of the invention is to provide means whereby when the lifting bar operated by the lifting jacks of apparatus of this class reaches a stationary support,

either temporary duringits movement, or permanent in its lowest position, the control of the screws upon the bar will be automatically disconnected without stopping the screw or breaking the apparatus; that is to say, the lifting screws then automatically cease to further lower the lifting bar with consequent danger of injury to the machine.

A further object is to, in combination withthe above, provide'means whereby the lifting bar will be automatically taken up by the lifting screws when their direction of motion is reversed, from lowering to raising.

The invention consists in a device capable of carrying out the foregoing objects, which can be'easily and cheaply made and installed, which is satisfactory in operation, and is not readily liable to get out of order and consists in details and features of construction which will be hereafter more fully described and claimed.

Referring to the drawlngs, Figure 1 is a vertical sectional detail viewtaken on the line 1-1 of Fig. 2 of a locomotive screw jack having the device of this invention in its preferred form incorporated. therein. Fig. 2 is a vertical sectional detail'view on the line 22 of Fig. 1. Fig. 3 is an enlarged sectional detail view on the same line showing certain details. Fig. 4 is a detail plan view on the line 4-4, of Fig. 3.

As is more fully shown in the above mentioned patent and application, devices of is rotatable at the will of the operator in either direction by means well known in the art illustrated, for instance, in the above patent and application. These trucks 12 may be. hand or power driven along the tracks 14, one hand mechanism which may be used comprising the lever 20 operated by a ratchet wheel 22 connected to a shaft 24 of the truck.

The cross beam or bar 18 which will be hereafter referred to at various places as a load bearing member and load support, is supported upon a pair of nuts 26 screw threaded as shown in the figures upon screw threads 15 of each main shaft 16 so that as each shaft 16 is rotated this nut travels upon the threads 15 and correspondingly supports the bar 18.

The nut 26 is made of noncircular cross section, as clearly appears in Fig. 2, and slidably but nonrotatively. fits into the block or hub 30 extending from the lower side of the adjacent end of beafn 18 which supports, bears, or carries the load, so that if the beam 18 be supported at any point desired and the shafts 16 are rotated to cause the nuts. 26 to travel downward thereon, said nuts will be thus withdrawn from the beam 18 without either crushing the temporary support for the load or breaking the lifting mechanism and the same advantage exists when permanent supports 32 are provided for the beam 18 in the-lowest normal position of the beam 18 in which the screw, and below the screw threads 15 thereon; or in other words, in' which the rotating shaft has no effect upon these nuts to move them farther downward and consequently to move the beam 18 below its fixed supports, for instance, the rests 32.

Under each nut 26 is a spring mechanism 40, in the particular case here illustrated a coil spring, of sufficient strength to lift the adjacent nut 26 and hold it in engagement with the lower end of the screw threads on shaft 16 so that when the shaft is rotated in lifting direction, the nut 26 will be readily taken up by the screw.

From the foregoing description of this mechanism is will be seen that when the parts are in the position of Fig. 2 and the shafts 16 are rotated, the bar 18 will be given motion upward or downward according to the rotation of the shafts 16. When, now, the shafts are rotated in the proper direction to lower beam 18 and said beam has reached the position where it rests upon the supports or rests 32, further rotation of the shafts 16 in this direction withdraws the nuts 26 out of the hubs 30 and the nuts 26 continue to move downward until they have traveled off from the screw threads 15 of the shafts 16 and rest quietly upon the springs 40, in which position the load beam [8 is carried at rest upon the supports 32;

p the nuts 26 exert no control upon the beam,

and consequently any neglect of the operator in allowing the screws 16 to continue to rotate in the direction just described, causes no damage whatever to any of the mechanism. When, however, the direction of rotation ofth'e shafts 16 is reversed, the nuts 26 being held in proximity to the lower ends of the screw threads 15 by the springs 40, the screws immediately take up the nuts 26, move themup into engagement with the beam 18 and then they begin to lift the load and move it up to and through the position of Fig. 2.

It is entirely obvious that the screw threads 15 may be omitted at the top of the shaft as well as at the bottom thereby pre- 'venting the nuts 26 from either traveling off from the upper end of the shaft if there is no top support or into engagement with .any supporting members which are provided at that point.

What we claim as new and desire to secure by Letters Patent, is:

1. In apparatus of the class described, the combination of a vertically mounted load carrying shaft, screw threads upon the shaft but extending less than its entire length, a nut adapted to travel upon the screw threads of said shaft of such a length that it can also lie in the non screw threaded portion of the shaft below the threaded portion, spring means urging said nut from 'the non-threaded to the threaded portion of said screw, and a load bearing membercarrying shaft, screw threads upon the shaft but extendin less than its entire length, a nut adapte to travel upon the screw threads of said shaft of such a length that it can also lie in the non screw threaded portion of the shaft below the threaded portion, spring means urging said nut from the non-threaded to the threaded portion of said screw, a load bearing member detachably connected to and supportable by said nut, and means supporting the load bearing member off from the nut when it clears the screw threads.

3. In apparatus of the class described, the combination of a vertically mounted load carrying shaft, screw threads upon the shaft but extending less than its entire length, a nut adapted to travel upon' the screw threads of said shaft of such a length that it can also lie in the non screw threaded portion of the shaft, a load bearing member detachably connected to and supportable by said nut, means supporting the load bearing member ofl" from the nut when it clears the screw threads, and spring means pressingthe nut, when off from the screw threads, toward said threads so that when the shaft is rotated in the direction for lifting the nut will be taken up by the screw threads.

.4. In apparatus of the class described, a vertically mounted load carrying shaft, plain for a space near its bottom, and screw threaded above, a nut adapted to selectively occupy said plain space or engage the screw threads and be propelled thereby, means pressing the nut when occupying the plain space into engagement with the end of the ,screw threads, a load support slidably but non-rotatively connected to the nut, and means supporting said load support off from the nut when the latter is in said plain space.

In witness whereof, we have hereunto subscribed our names in the presence of two witnesses.

CLEMENT A. HARDY. RALPH H. BOURNE. Witnesses:

A. J. THOMAS, N. S. LAURENCE. 

